Dopant chemical anchoring enables ultra-low interfacial thermal resistance composite phase-change metal foil with high reliability for efficient heat dissipation

Abstract

Non-gallium alloys, such as Field's Metal (FM), are anticipated to be one of the most promising low-melting-point metal thermal interface materials (TIMs) for the thermal management of high heat-load chips owing to their unique solid–liquid phase change characteristics. However, the prerequisite is to develop new composite materials based on non-gallium alloys and solve the heterogeneous hybrid interface bonding issue, thereby overcoming the challenges of processing and shaping them as well as mitigating the risk of leakage during phase change simultaneously. Herein, we propose a metal-interface covalent bonding strategy based on FM and the doping of surface-fluorinated copper particles (CuP@F), developing novel composite phase change metal foil (CuP@F/FMF) characterized by high reliability and ultra-low interface total thermal resistance (R_total). Cu–O–Si and F–Bi bonds were formed between CuP@F and FM via triethoxy(3,3,3-trifluoropropyl)silane, thereby significantly enhancing the binding strength of the hybrid interface. Owing to the formation of chemical bonds, FM was anchored by CuP@F, resulting in an increase in plasticity and a decrease in the fluidity of the composites compared to pure FM. Consequently, the ultrathin CuP@F/FMF was successfully fabricated, effectively preventing liquid metal leakage during the solid–liquid phase change, even under a compressive stress of 100 psi. CuP@F/FMF exhibited an ultralow R_total of 0.012 cm² K W⁻¹, lower than that of previously reported phase change TIMs (PCTIMs) and liquid metal-based TIMs. Its performance in cooling chips significantly surpassed that of commercial PCTIMs. This study provides a transformative approach to advancing the synthesis of non-gallium alloy-based composites and their applications in thermal management technology.